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Banging Pipes

Why does the sewage pump cause a racket?

Richard Trehewey holds a toilet

I live in a four-year-old, 3,000-square-foot house that has a sewage pump in the basement. When it pumps the water up and out, I can hear the water go into the main sewer line, but the PVC pipe from the pump to the main jumps and bangs at the completion of the cycle. The banging is driving me nuts. Could it be the pump is getting air in the line? Will this banging hurt the pump?



Richard Trethewey replies: A sewage ejector allows you to have a bathroom at a level that is below the height of the main drain pipe that leaves the building. Waste water from some or all of the bathrooms goes into a recessed sump bucket in the basement floor. As the level rises, a float activates a pump that pumps the water into the main drain.

First, be sure there's a check valve installed on the outlet from the pump. This means the water only leaves the sump and doesn't return. Remember there is tremendous inertia as this very strong pump comes on. Be sure the piping is hung and supported well to hold it in place.
After doing that, if there is still too much noise, check with a plumber to see whether the pump is too big; if it's oversized it should be replaced with the correct size.


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